Umbrella



FIG. 1 is an isometric view of the umbrella of the present design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevation view thereof, the rear elevation view being identical thereto;

FIG. 4 is a right side elevation view, the left side elevation view being identical thereto; and,

FIG. 5 is a bottom plan view thereof. 

The ornamental design for an umbrella, as shown and described. 